Method for manufacturing pneumatic tire

Abstract

A method for manufacturing a pneumatic tire includes preparing a sheet made from a thermoplastic resin or a thermoplastic resin composition which is a blend of the thermoplastic resin and an elastomer, tip-sharpening end portions of the sheet to form sharpened tips, preparing a laminate by laminating the sheet and a rubber such that the rubber forms an inner layer with respect to the sheet, lap-splicing end portions of the laminate, which include the sharpened tips of the sheet, to form a lap splice portion, and curing and molding the laminate in which the lap splice portion is formed to form an inner liner layer of the pneumatic tire after the tip-sharpening of the end portions of the sheet.

What is claimed is: 
     
         1 . A method for manufacturing a pneumatic tire, the method comprising:
 preparing a sheet made from a thermoplastic resin or a thermoplastic resin composition which is a blend of the thermoplastic resin and an elastomer;   tip-sharpening end portions of the sheet to form sharpened tips;   preparing a laminate by laminating the sheet and a rubber such that the rubber forms an inner layer with respect to the sheet;   lap-splicing end portions of the laminate, which include the sharpened tips of the sheet, to form a lap splice portion; and   curing and molding the laminate in which the lap splice portion is formed to form an inner liner layer of the pneumatic tire after the tip-sharpening of the end portions of the sheet.   
     
     
         2 . The method for manufacturing the pneumatic tire according to  claim 1 , wherein
 the lap-splicing of the end portions of the laminate is performed with the rubber having straight edge portions that are parallel to a lamination direction in which the sheet and the rubber are laminated.   
     
     
         3 . The method for manufacturing the pneumatic tire according to  claim 1 , wherein
 each of the sharpened tips of the sheet has a thickness T (μm) that has a relationship which satisfies 0.1t≤T≤0.8t, where   t represents an average thickness (μm), in a lamination direction in which the sheet and the rubber are laminated, of a tip-sharpening-unprocessed part of the sheet, and   T represents the thickness (μm) of the sheet in a location inward in a circumferential direction by a length (t×⅓) from an end of each of the sharpened tips of the sheet.   
     
     
         4 . The method for manufacturing the pneumatic tire according to  claim 3 , wherein
 each of the sharpened tips of the sheet extends in a length L to a location inward in the circumferential direction from an end of each sharpened tip, with the length L being expressed by L=(1.0 to 20)×t (μm).   
     
     
         5 . The method for manufacturing the pneumatic tire according to  claim 3 , wherein
 each of the sharpened tips of the sheet extends in a length L to a location inward in the circumferential direction from an end of each sharpened tip, with the length L being expressed by L=(1.0 to 2.5)×t (μm).   
     
     
         6 . The method for manufacturing the pneumatic tire according to  claim 1 , wherein
 the sheet is made from the thermoplastic resin composition which is the blend of the thermoplastic resin and the elastomer, and   the tip-sharpening of the end portions of the sheet is performed by thermal cutting such that the thermoplastic resin flows on surfaces of the sharpened tips to form a film of the thermoplastic resin covering the elastomer at the sharpened tips.   
     
     
         7 . The method for manufacturing the pneumatic tire according to  claim 1 , wherein
 the tip-sharpening of the end portions of the sheet is performed after the laminating of the sheet and the rubber.   
     
     
         8 . The method for manufacturing the pneumatic tire according to  claim 7 , further comprising
 the tip-sharpening of the end portions of the sheet is performed by cutting the laminate.   
     
     
         9 . The method for manufacturing the pneumatic tire according to  claim 8 , wherein
 the cutting of the laminate includes thermally cutting the laminate using a heat cutter.   
     
     
         10 . The method for manufacturing the pneumatic tire according to  claim 1 , wherein
 the tip-sharpening of the end portions of the sheet is performed before the laminating of the sheet and the rubber.   
     
     
         11 . The method for manufacturing the pneumatic tire according to  claim 10 , further comprising
 the tip-sharpening of the end portions of the sheet is performed by cutting the sheet.   
     
     
         12 . The method for manufacturing the pneumatic tire according to  claim 12 , wherein
 the cutting of the sheet includes thermally cutting the sheet using a heat cutter.